1. Technical Field
The present invention relates to electronic apparatuses in general, and in particular to a technique for switching access points of a wireless network via sharing communications.
2. Description of Related Art
A wireless network can be classified into a wireless personal area network (PAN), a wireless local area network (LAN), a wireless metropolitan area network (MAN), and a wireless wide area network (WAN), from a point of view of a service region reached by radio waves. These wireless networks are connected to one another via a backbone network. Each wireless network includes a wireless base station or an access point (AP) to which wireless terminal devices are wirelessly connected. When each of the wireless terminal devices is connected to the AP, the device can be connected to the other wireless terminal device connected to each wireless network, or can access each wireless network.
A round areal region defined as the radio wave reaching region covered by the AP is called a cell. The wireless LAN is formulated by IEEE 802.11WG, and the cell is comparatively small. The wireless LAN is called WiFi sometimes, because WiFi alliance provides a use compatibility to products which conform to 802.11 standard specifications and performs mutual authentication.
The wireless MAN is formulated by IEEE 802.16WG, and called WiMAX, because WiMAX forum authenticates a product that conforms to IEEE 802.16 standard specifications. A cell of WiMAX is larger than that of the wireless LAN. Mobile WiMAX has a size of a cell which is about the same as that of a cellular phone network, but has a purpose of performing data communication of a broad band in an area smaller than that of the cellular phone network.
The wireless WAN is a network built by a mobile communication company, and has communication standards such as 3G, 3.5G, and LTE (4G) formulated by 3GPP/3GPP2 of ITU-R. A cell of the wireless WAN is the largest among the cells. On a wireless terminal device such as a notebook type personal computer (hereinafter referred to as the laptop PC), a tablet terminal or a smartphone, there is mounted a wireless adapter (or network interface card) usually for connection to the wireless LAN. Moreover, on some of these devices, a wireless MAN adapter and a wireless WAN adapter are mounted in addition to the wireless LAN adapter.
When multiple wireless adapters are mounted on one laptop PC, opportunities for the connection to the wireless networks can be increased. When one user carries multiple wireless terminal devices or multiple users move together carrying the wireless terminal devices, respectively, the wireless terminal device on which the only wireless LAN adapter is mounted is to be connected to the internet via the wireless MAN or the wireless WAN in a place where there are not any access points of the wireless LAN sometimes.
On Windows® 7 of Microsoft Corporation, functions such as Virtual WiFi, SoftAP and internet connection sharing (ICS) are mounted. Virtual WiFi is a function of operating one wireless LAN adapter as a set of wireless LAN adapters by virtualization. The SoftAP is a function of emulating the function of the AP of the wireless LAN with software so as to operating as a virtual AP. The ICS is a technology in which one host to be connected to an internet service provider (ISP) is determined among a set of wireless terminal devices on which the wireless LAN adapters are mounted, so that the other wireless terminal devices which become clients can be connected to the internet through the host.
In addition, there is a technology such as My WiFi Technology (MWT) of Intel Corporation, or Wi-Fi Direct formulated by Wi-Fi Alliance which is a U.S. wireless LAN industry group, in which one wireless LAN adapter is operated as two network adapters by the virtualization with software.